The Biostatistics/Data Management Center - Radiation Therapy Oncology Group (RTOG) will provide the centralized data management and biostatistical support for the chemoprevention study (Project 1) and develop a quantitative risk assessment model (Project 2). The nutritional, behavioral, and analytic chemistry data which are generated for Projects 1 and 2 will also be the responsibility of the RTOG Center. They will be integrated with the clinical data derived from the chemoprevention study for analyses. Although the final repository for all the data needed for the analyses of Project 2 and will be the RTOG Center, intermediate data collection and processing will be performed at the Biostatistics/Data Management Center - M.D. Anderson Cancer Center (MDACC). The functional tasks to be performed by the RTOG Center include: 1) biostatistical support; 2) standardization of mechanisms; 3) patient registration and randomization; 4) collection, review, and computerization of clinical data; 5) biological specimens: tracking their receipt, routing to the pertinent cores, and incorporating the results of the core's analyses; 6) monitoring the quality of the submitted clinical data; 7) toxicity surveillance; 8) on-site audits of the RTOG institutions and MDACC; 9) monitoring the progress of Projects 1 and 2 by preparation of semi-annual reports; 10) monitoring performance of the participating institutions annually. The RTOG Biostatistics/Data Management Center will utilize the resources of the American College of Radiology in Philadelphia where the data management and the biostatistical support for the RTOG studies are already provided. The staff of the RTOG Center has participated in the design, data collection and monitoring, analyses, and reporting of over 25 multi-center head and neck studies. The staff has experience in providing the data management and biostatistical support for nine intergroup studies in which two or more cancer cooperative groups have contributed patients. Ancillary studies that collect tissue material for central laboratory review in conjunction with RTOG clinical trials have also been supported by the staff.